1. Field of the Invention
The present invention generally relates to exothermic combustion, and more particularly to a method of enhancing the combustion process to improve its efficiency and reduce the creation or emission of pollutants.
2. Description of the Related Art
Combustion is one of the oldest and perhaps most studied of all chemical reactions. From the beginning of human existence through today, combustion has been the medium of many quality-of-life improvements. It is essential to our present everyday life experience in several forms. Major subsets of combustion applications include transportation, electricity generation and indoor heating.
Combustion is an exothermic chemical reaction whereby a fuel source is oxidized. Fuel sources utilized for combustion are almost always hydrocarbon materials. The most common examples are different forms of petroleum products, such as natural gas, diesel and coal. Although each of these fuel sources contains various fractional amounts of non-hydrocarbons, carbon and hydrogen are the major fuel source components of the combustion process. In addition, various fuel sources inherently are composed of different percentages of hydrogen and carbon. For example, coal has a higher composition percentage of carbon than natural gas (methane) and vice versa for hydrogen. These fuel sources are generally oxidized by way of oxygen in the air. During the combustion process, hydrogen and carbon molecules separate and reform with unbound oxygen to form the two major by-products of combustion, carbon dioxide (CO2) and water (H2O).
A great amount of time, effort and capital has been invested in past attempts toward the goal of improved combustion efficiency. These efforts include a wide spectrum of approaches such as modification of the combustion process itself, to peripheral areas of improvement in combustion mechanisms and end-product delivery distribution equipment. On the surface, analysis and understanding of the basic combustion process appears fairly simple and straightforward. The reality is quite the opposite, with extremely complex chemical transformations occurring at the atomic level. Much remains unknown even today about these atomic interactions.
One serious problem with combustion that remains is the level of pollutant by-products. Coal, diesel and gas power plants produce a variety of pollutants, such as particulates, various oxides of sulfur (primarily SO2, collectively referred to as SOx), and nitric oxides (NO or NO2, collectively referred to as NOx). Automobiles are also known to produce high levels of NOx as well as hydrocarbons that can damage the sensitive ozone layer surrounding the Earth. Air pollution regulations have become increasingly tougher as combustion-based power production has grown. The problem is still apparent, not only in industrial centers, but in most mid-size and larger cities where smog and ozone alerts have become commonplace.
Assorted techniques have been devised to reduce combustion pollutants, by either reducing their formation during the combustion processes, or removing them from the exhaust stream. Various catalysts can also be used to reduce pollutant production. For example, a ceramic structure such as zeolite (hydrated aluminum and calcium/sodium silicate made with a controlled porosity) coated with a metal such as platinum, rhodium or palladium is commonly used to catalyze the reduction of nitric oxides.
It is difficult, however, to achieve complete (efficient) combustion combined with low NOx emissions. Sophisticated high-temperature, multi-stage combustion processes can be used, but these arrangements are typically expensive and not particularly efficient. One design which addresses these issues is shown in U.S. Pat. No. 4,728,282. The disclosed apparatus is a furnace designed to carry out a substantially isothermal combustion process using some combination of: (i) controlled radiation in the vicinity of flame emission with the combustor; (ii) temperature-responsive, controlled flow rate increase of recirculation of exhausted gases including recirculated heat and water vapor into the primary combustion zone; and (iii) controlled staged oxidation of and heat extraction from each of a plurality of oxidation or combustion zones.
Another approach to more efficient combustion and pollution control is to activate fuel components prior to combustion, as discussed in U.S. Pat. No. 3,976,726. That fuel activation apparatus subjects the fuel components to pulsed energy from an oscillator at a frequency in a range corresponding to resonant frequencies for the molecular components or constituent elements of the fuel. The operating frequency range may be expanded to include the nuclear resonance frequency for such components.
Nuclear resonance is a phenomenon associated with the protons or nuclei of an element. The nuclei of all elements carry a charge. When the spins of the protons comprising a nucleus are not paired, the overall spin of the charged nucleus generates a magnetic dipole along the spin axis. The intrinsic magnitude of this dipole is a fundamental nuclear property called the nuclear magnetic moment. Certain atoms and molecules can be excited by the application of an electromagnetic field which interacts with the magnetic dipoles formed by the nuclei. Not all nuclei possess spin (i.e., their spin number is 0), and those elements having no nuclear spin (and hence, no dipole moment) cannot be affected using nuclear resonance. Abundant elemental components of combustion that have spin numbers of 0 and therefore are not candidates for nuclear resonation include C-12 and O-16.
Nuclear magnetic resonance (NMR) utilizes a static magnetic field and a second oscillating magnetic field to perturb the nuclei of material under inspection. The rotational axis of a spinning nucleus is not orientated exactly parallel (or anti-parallel) with the direction of the applied magnetic field, but rather precesses about this field at a known angle and with an angular velocity that depends upon the magnetic moment. A given set of distinct protons transitioning between quantum states will produce an electromagnetic (sine) wave whose frequency matches their precession frequency. The effective magnetic field around a given nucleus can also be affected by the orientation of neighboring nuclei, and may lead to spin-spin coupling which splits the signal for each type of nucleus into two or more spectral lines. The signal detected at the NMR receiver thus resembles a collection of exponentially decaying sine waves, and is referred to as a free induction decay (FID). Analysis of the FID yields frequencies associated with known chemical structures. Two-dimensional spectroscopy techniques are used to determine the structure of more complicated molecules. NMR has heretofore been used primarily for imaging purposes, such as in magnetic resonance imaging (MRI) for medical diagnostics. Important elemental components of combustion susceptible to NMR manipulation include the nuclei of the H-1 isotope when combined with carbon in hydrocarbon molecules.
Some nuclei, such as nitrogen-14, possess electric quadrupole moments (non-spherical electric charge distributions). Nuclear quadrupole resonance (NQR) can be utilized on such substances. NQR is a branch of radio frequency spectroscopy that has been used quite effectively for the detection of contraband and other items of concern such as explosives. A radio frequency pulse generated by a transmitter coil causes the excitation of nuclear spins to higher quantum energy levels. When the nuclear spins return to their equilibrium position, they again follow a particular precession frequency based on their quadrupole moments. In NQR substance detection, a receiving coil is used to measure and analyze the energy released from the resonated nuclei as they return to their normal spin states. Measurement of this released energy (and/or relaxation time constants) can indicate not only which nuclei are present but also their chemical environment. The environmental variables of temperature, pressure, and molecular composition (as opposed to free-form or unbound atoms) will alter the resonant frequencies and spin relaxation times of otherwise identical isotopes of NMR/NQR receptive elements.
Relaxation times are inherently much shorter in the science of NQR as opposed to NMR. Therefore, this is a critical consideration in the placement of NMR/NQR components in various combustion enhancement systems. Exact relaxation times for different combustion techniques can vary considerably; however, for the combustion techniques contemplated by the present invention, it is believed that they are approximately 1 second for NMR targeted substances and 0.001 second for NQR targeted substances. Two general problems with NQR relate to the long recovery time of the signal stimulus/receiver coil (ring-down), and the echoing of input signals off metallic objects.
While NMR and NQR have proved valuable in such applications as imaging and identification of chemical structures, these techniques have not been effectively applied to the combustion process itself. It would, therefore, be advantageous to devise a method of enhancing the combustion process to reduce the formation or emission of pollutants using nuclear resonance. It would be further desirable if the method could enhance combustion efficiency as well.